Heat exchanger fin, heat exchanger, condensers, and evaporators

ABSTRACT

A heat exchanger fin, capable of improving heat transfer rate while preventing generation of heat bypass flow, such as a louver fin provided with a plurality louvers arranged at certain intervals in the introduction direction of air. The louvers are formed by cutting and bending the heat exchanger fin so that the air is passed while being guided by the louvers. The plurality of louvers include louvers different in louver width, the louver width being defined by a length of the louver along which the heat medium passes. Wider louvers and narrower louvers can be arranged alternatively.

Priority is claimed to Japanese Patent Application No. 2003-140400 filed on May 19, 2003, and U.S. Provisional Application No. 60/478,360 filed on Jun. 16, 2003, the disclosure of which are incorporated by reference in their entireties.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is an application filed under 35 U.S.C. § 111(a) claiming the benefit pursuant to 35 U.S.C. § 119(e) (1) of the filing date of Provisional Application No. 60/478,360 filed on Jun. 16, 2003 pursuant to 35 U.S.C. § 111 (b).

TECHNICAL FIELD

The present invention relates to a heat exchanger such as a car air-conditioning condenser or evaporator for use in car air-conditioning refrigeration cycles as a car air-conditioning apparatus for example. It also relates to a fin for use in heat exchangers (hereinafter referred to as “heat exchanger fin”) such as a louver fin or a corrugated fin to be equipped to the aforementioned apparatuses.

BACKGROUND ART

A heat exchanger such as an evaporator or a condenser for use in car air-conditioning refrigeration cycles includes a heat exchanging tube through which refrigerant passes and a heat exchanger fin disposed perpendicular to the longitudinal direction of the heat exchanging tube, so that heat exchanging is performed between the ambient air and the refrigerant passing through the heat exchanging tube via the fin.

As a heat exchanger fin, depending on the usage and/or required performance, a louver fin, an offset fin, a pin fin and the like has been commonly used.

Among heat exchanges, in a louver fin type heat exchanger, as shown in FIG. 11, a plurality of louver fins 50 arranged in parallel to the introduction direction X of the air A are arranged in parallel with each other at certain intervals in the direction perpendicular to the air introduction direction X, thereby forming an air passages 60 between the adjacent louver fins 50. Each louver fin 50 is provided with a plurality of cut-and-bent louvers 51 arranged in the longitudinal direction (air introduction direction) of the air passage 60. The air A introduced in each air passage 60 passes through the louver gaps each formed between the adjacent louvers 51 of each louver fin 50 along the louvers 51, thereby exchanging heat between the air A and the refrigerant passing through the heat exchanging tube (not shown).

As one of the methods for improving the thermal performance in such heat exchangers, it may be considered effective to increase the contact area between the windward side edges of the louvers 51 and the air A by decreasing the pitch of the louvers 51 to increase the number of louvers 51.

However, the smaller louver pitch may cause clogging of sand and/or bridging of condensed water between the adjacent louvers 51, preventing the air A passing through the air passage 60 from being introduced into the louver gaps each formed between the adjacent louvers 51. This causes the bypass flow of the air A, i.e., the air flow passing through the fin spaces each formed between the adjacent louver fins 50 without being introduced into the louver gaps, resulting in a deterioration of the heat transfer rate.

On the other hand, in a louver fin type heat exchanger, Japanese Unexamined Laid-open Patent Publication No. H6-221787 (FIGS. 1 and 3) and U.S. Pat. No. 5,730,214 (FIGS. 5 to 7) disclose techniques for improving the heat exchanging performance by changing the angle of the louver.

Furthermore, disclosed in Japanese Unexamined Laid-open Patent Publication No. H1-263498 (pages 1 to 2) is a technique in which the optimal values of the fin pitch, the fin thickness, the louver pitch and the louver angle are defined.

In the recent technical field of heat exchangers, especially in the technical field of car air-conditioning heat exchangers, however, it is requested to further improve the heat exchanging performance. Therefore it is also requested to further improve the heat transfer rate of the heat exchanger fin.

It is an object of the present invention to provide a heat exchanger such as a car air-conditioning condenser or evaporator improved in heat transfer rate and therefore excellent in heat exchanging performance.

It is another object of the present invention to provide a heat exchanger fin such as a louver fin and a corrugated fin to be equipped to the aforementioned heat exchangers.

DISCLOSURE OF INVENTION

In order to attain the aforementioned objects, the present invention has the following features.

[1] A heat exchanger fin, comprising:

a heat transfer plate disposed in parallel to a heat medium introduction direction and provided with a plurality louvers arranged at certain intervals in the heat medium introduction direction, said plurality of louvers being formed by cutting and bending said heat transfer plate so that the heat medium is passed while being guided by said plurality of louvers,

wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the heat medium passes, and

wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement along the heat medium introduction direction.

In the heat exchanger fin according to the present invention, since a plurality of louvers include plural kinds of louvers different in louver width, the heat medium such as air will be assuredly introduced into the gaps each formed between the adjacent louvers to flow smoothly along each louver, resulting in improved heat transfer rate by preventing generation of bypass flow of the heat medium.

[2] The heat exchanger fin as recited in the aforementioned Item [1], wherein said plurality of louvers include wide louvers each having a wide louver width and narrow louvers each having a narrow louver width, wherein said wide louvers and said narrow louvers are disposed in a mixed arrangement.

[3] The heat exchanger fin as recited in the aforementioned Item [2], wherein one or a plurality of said wide louvers and one or a plurality of said narrow louvers are arranged alternatively.

[4] The heat exchanger fin as recited in the aforementioned Item [2], wherein said wide louver and said narrow louver are arranged alternatively.

In the invention as recited in the aforementioned Items [2] to [4], since two kinds of louvers are employed, the heat transfer rate can be further improved without complicating the structure.

[5] The heat exchanger fin as recited in any one of the aforementioned Items [2] to [4], wherein when a louver width of said wide louver and a louver width of said narrow louver are represented as “Lwl” and “Lws,” respectively, a ratio “Lws/Lwl” of said louver width “Lws” of said narrow louver to said louver width “Lwl” of said wide louver is set to 0.1 to 0.7.

[6] The heat exchanger fin as recited in any one of the aforementioned Items [1] to [5], wherein an angle of said louver (louver angle) with respect to said heat transfer plate is set to 22 to 36°.

In the invention as recited in the aforementioned Items [5] and [6], the heat transfer rate can be further improved.

[7] The heat exchanger fin as recited in any one of the aforementioned Items [1] to [6], wherein a plurality of said heat transfer plates are arranged in parallel with each other at certain intervals in a direction perpendicular to the heat medium introduction direction to form an air passage between adjacent heat transfer plates.

As will be understood from the aforementioned Item [7], the present invention can be preferably employed as corrugated fins or plate fins.

[8] The heat exchanger fin as recited in the aforementioned Item [7], wherein a fin pitch defined by a distance between adjacent heat transfer plates is set to 1 to 2 mm.

In the invention as recited in the aforementioned Item [8], the heat transfer rate can be further improved.

[9] The heat exchanger fin as recited in the aforementioned Item [7] or [8], wherein when a fin pitch defined by a distance between adjacent heat transfer plates is represented as “Fp” and a louver width of a widest louver having a widest width is represented as “Lwmax,” a ratio “Fp/Lwmax” of said fin pitch “Fp” with respect to said louver width “Lwmax” is set to 1 or more.

In the invention as recited in the aforementioned Item [9], the heat transfer rate can be further improved.

[10] The heat exchanger fin as recited in any one of the aforementioned Items [1] to [9], wherein said heat transfer plate is disposed between said pair of heat exchanging tubes arranged in parallel with each other at a certain distance to exchange heat between air as a heat medium passing through said pair of heat exchanging tubes and refrigerant passing through said heat exchanging tube.

As will be understood from the aforementioned Item [10], the present invention can be preferably employed in tube type heat exchangers.

[11] The heat exchanger fin as recited in the aforementioned Item [10], wherein it is configured such that refrigerant is condensed by exchanging heat with air.

As will be understood from the aforementioned Item [11], the present invention can be preferably employed in condensers.

[12] The heat exchanger fin as recited in the aforementioned Item [10], wherein it is configured such that refrigerant is evaporated by exchanging heat with air.

As will be understood from the aforementioned Item [12], the present invention can be preferably employed in evaporators.

The preferable features as recited in the aforementioned Items [2[ to [12] can also be employed in the following Items [13] to [30].

[13] A louver fin, comprising:

a heat transfer plate disposed in parallel to a heat medium introduction direction and provided with a plurality louvers arranged at certain intervals in the heat medium introduction direction, said plurality of louvers being formed by cutting and bending said heat transfer plate so that the heat medium is passed while being guided by said plurality of louvers,

wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the heat medium passes, and

wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement along the heat medium introduction direction.

In the louver fin according to the invention, in the same manner as mentioned above, the heat medium such as air will be assuredly introduced in between louvers to flow smoothly along each louver, enabling improvement of the heat transfer rate by preventing generation of bypass flow.

[14] A corrugated fin, comprising:

a plurality of heat transfer plates disposed in parallel to a heat medium introduction direction and arranged in parallel at certain intervals in a direction perpendicular to the heat medium introduction direction with adjacent heat transfer plates connected with each other, each of said plurality of heat transfer plates being provided with a plurality louvers arranged at certain intervals in the heat medium introduction direction, said plurality of louvers being formed by cutting and bending said heat transfer plate so that the heat medium is passed while being guided by said plurality of louvers,

wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the heat medium passes, and

wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.

In the corrugated fin according to the invention, in the same manner as mentioned above, the heat medium such as air will be assuredly introduced in between louvers to flow smoothly along each louver, enabling improvement of the heat transfer rate by preventing generation of bypass flow.

[15] A heat exchanger, comprising a plurality of heat exchanger fins disposed in parallel to an air introduction direction and arranged in parallel at certain intervals in a direction perpendicular to the air introduction direction, and a refrigerant passage through which refrigerant passes, each of said plurality of heat transfer plates being provided with a plurality louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to exchange heat between the air and the refrigerant,

wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the heat medium passes, and

wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.

In the heat exchanger according to the invention, in the same manner as mentioned above, the heat medium such as air will be assuredly introduced in between louvers to flow smoothly along each louver, enabling improvement of the heat transfer rate by preventing generation of bypass flow.

[16] A heat exchanger, comprising a pair of heat exchanging tubes disposed in parallel at a certain interval, and a plurality of heat exchanger fins each disposed in parallel to an air introduction direction and arranged in parallel with each other at certain intervals in a direction perpendicular to the air introduction direction, and each of said plurality of heat exchanger fins being provided with a plurality louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to exchange heat between the air and the refrigerant,

wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the air passes, and

wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.

In the heat exchanger according to the invention, in the same manner as mentioned above, the heat medium such as air will be assuredly introduced in between louvers to flow smoothly along each louver, enabling improvement of the heat transfer rate by preventing generation of bypass flow.

[17] The heat exchanger as recited in the aforementioned Item [15] or [16], wherein said plurality of louvers include wide louvers each having a wide louver width and narrow louvers each having a narrow louver width, wherein said wide louvers and said narrow louvers are disposed in a mixed arrangement.

In the invention as recited in the aforementioned Item [17], in the same manner as mentioned above, the heat transfer rate can be further improved.

[18] The heat exchanger as recited in the aforementioned Item [15] or [16], wherein adjacent fins among said plurality of heat exchanger fins are joined with each other.

As will be understood from the aforementioned Item [18], the present invention can be preferably employed in corrugated type heat exchangers.

[19] A condenser, comprising a plurality of heat exchanger fins disposed in parallel to an air introduction direction and arranged in parallel at certain intervals in a direction perpendicular to the air introduction direction, and a refrigerant passage through which refrigerant passes, each of said plurality of heat transfer plates being provided with a plurality louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to condense the refrigerant by exchange heat between the air and the refrigerant,

wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the heat medium passes, and

wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.

In the condenser according to the invention, in the same manner as mentioned above, the heat medium such as air will be assuredly introduced in between louvers to flow smoothly along each louver, enabling improvement of the heat transfer rate by preventing generation of bypass flow.

[20] A condenser, comprising a pair of heat exchanging tubes disposed in parallel at a certain interval, and a plurality of heat exchanger fins each disposed in parallel to an air introduction direction and arranged in parallel with each other at certain intervals in a direction perpendicular to the air introduction direction, and each of said plurality of heat exchanger fins being provided with a plurality louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to condense refrigerant by exchanging heat between the air and the refrigerant,

wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the air passes, and

wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.

In the condenser according to the invention, in the same manner as mentioned above, the heat medium such as air will be assuredly introduced in between louvers to flow smoothly along each louver, enabling improvement of the heat transfer rate by preventing generation of bypass flow.

[21] The condenser as recited in the aforementioned Item [19] or [20], wherein said plurality of louvers include wide louvers each having a wide louver width and narrow louvers each having a narrow louver width, wherein said wide louvers and said narrow louvers are disposed in a mixed arrangement.

In the invention as recited in the aforementioned Item [21], in the same manner as mentioned above, the heat transfer rate can be further improved.

[22] The condenser as recited in the aforementioned Item [19] or [20], wherein adjacent fins among said plurality of heat exchanger fins are joined with each other.

As will be understood from the aforementioned Item [22], the present invention can be preferably employed in corrugated type heat exchangers.

[23] A condenser for use in car air-conditioning refrigeration cycles, comprising:

a plurality of heat exchanger fins disposed in parallel to an air introduction direction and arranged in parallel at certain intervals in a direction perpendicular to the air introduction direction; and

a refrigerant passage through which refrigerant passes,

wherein each of said plurality of heat transfer plates is provided with a plurality louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to condense the refrigerant by exchange heat between the air and the refrigerant, and

wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the heat medium passes, and

wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.

In the car air-conditioning condenser according to the invention, in the same manner as mentioned above, the heat medium such as air will be assuredly introduced in between louvers to flow smoothly along each louver, enabling improvement of the heat transfer rate by preventing generation of bypass flow.

[24] A condenser for use in car air-conditioning refrigeration cycles, comprising:

a pair of heat exchanging tubes disposed in parallel at a certain interval; and

a plurality of heat exchanger fins each disposed in parallel to an air introduction direction and arranged in parallel with each other at certain intervals in a direction perpendicular to the air introduction direction, wherein each of said plurality of heat exchanger fins is provided with a plurality louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to condense refrigerant by exchanging heat between the air and the refrigerant,

wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the air passes, and

wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.

In the car air-conditioning condenser according to the invention, in the same manner as mentioned above, the heat medium such as air will be assuredly introduced in between louvers to flow smoothly along each louver, enabling improvement of the heat transfer rate by preventing generation of bypass flow.

[25] An evaporator, comprising a plurality of heat exchanger fins disposed in parallel to an air introduction direction and arranged in parallel at certain intervals in a direction perpendicular to the air introduction direction, and a refrigerant passage through which refrigerant passes, each of said plurality of heat transfer plates being provided with a plurality louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to evaporate the refrigerant by exchange heat between the air and the refrigerant,

wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the heat medium passes, and

wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.

In the evaporator according to the invention, in the same manner as mentioned above, the heat medium such as air will be assuredly introduced in between louvers to flow smoothly along each louver, enabling improvement of the heat transfer rate by preventing generation of bypass flow.

[26] An evaporator, comprising a pair of heat exchanging tubes disposed in parallel at a certain interval, and a plurality of heat exchanger fins each disposed in parallel to an air introduction direction and arranged in parallel with each other at certain intervals in a direction perpendicular to the air introduction direction, and each of said plurality of heat exchanger fins being provided with a plurality louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to evaporate refrigerant by exchanging heat between the air and the refrigerant,

wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the air passes, and

wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.

In the evaporator according to the invention, in the same manner as mentioned above, the heat medium such as air will be assuredly introduced in between louvers to flow smoothly along each louver, enabling improvement of the heat transfer rate by preventing generation of bypass flow.

[27] The evaporator as recited in the aforementioned Item 25 or 26, wherein said plurality of louvers include wide louvers each having a wide louver width and narrow louvers each having a narrow louver width, wherein said wide louvers and said narrow louvers are disposed in a mixed arrangement.

In the invention as recited in the aforementioned Item [27], in the same manner as mentioned above, the heat transfer rate can be further improved.

[28] The evaporator as recited in the aforementioned Item [25] or [26], wherein adjacent fins among said plurality of heat exchanger fins are joined with each other.

As will be understood from the aforementioned Item [28], the present invention can be preferably employed in corrugated type evaporators.

[29] An evaporator for use in car air-conditioning refrigeration cycles, comprising:

a plurality of heat exchanger fins disposed in parallel to an air introduction direction and arranged in parallel at certain intervals in a direction perpendicular to the air introduction direction; and

a refrigerant passage through which refrigerant passes,

wherein each of said plurality of heat transfer plates is provided with a plurality louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to evaporate the refrigerant by exchange heat between the air and the refrigerant, and

wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the heat medium passes, and

wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.

In the evaporator according to the invention, in the same manner as mentioned above, the heat medium such as air will be assuredly introduced in between louvers to flow smoothly along each louver, enabling improvement of the heat transfer rate by preventing generation of bypass flow.

[30] An evaporator for use in car air-conditioning refrigeration cycles, comprising:

a pair of heat exchanging tubes disposed in parallel at a certain interval; and

a plurality of heat exchanger fins each disposed in parallel to an air introduction direction and arranged in parallel with each other at certain intervals in a direction perpendicular to the air introduction direction, wherein each of said plurality of heat exchanger fins is provided with a plurality louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to evaporate refrigerant by exchanging heat between the air and the refrigerant,

wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the air passes, and

wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.

In the evaporator according to the invention, in the same manner as mentioned above, the heat medium such as air will be assuredly introduced in between louvers to flow smoothly along each louver, enabling improvement of the heat transfer rate by preventing generation of bypass flow.

Another objects and advantages of the invention will be more clearly apparent from the following explanations.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective cut-out explanatory view partially showing a fin and its vicinity of a heat exchanger according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view taken along the line P-P in FIG. 1 and showing the louver fin of the aforementioned embodiment.

FIG. 3 is an enlarged cross-sectional view showing the fin portion of the heat exchanger according to the aforementioned embodiment.

FIGS. 4(a) to 4(e) show partial cross-sectional views of louver fins according to modified embodiments of the present invention.

FIG. 5 is a graph showing the relationship between the front wind velocity and the heat transfer rate in the evaporators of Examples 1 to 5 and Comparative Example 1.

FIG. 6 is a graph showing the relationship between the front wind velocity and the heat transfer rate in the evaporators of Examples 6 and 7 and Comparative Example 2.

FIG. 7 is a graph showing the relationship between the louver angle and the heat transfer rate at the front wind velocity of 1 m/s in the evaporators of Examples 8 and 9 and Comparative Example 3.

FIG. 8 is a graph showing the relationship between the louver angle and the heat transfer rate at the front wind velocity of 2 m/s in the evaporators of Examples 8 and 9 and Comparative Example 3.

FIG. 9 is a graph showing the relationship between the fin pitch and the heat transfer rate at the front wind velocity of 1 m/s in the evaporators of Examples 9 and 10 and Comparative Example 4.

FIG. 10 is a graph showing the relationship between the fin pitch and the heat transfer rate at the front wind velocity of 2 m/s in the evaporators of Examples 10 and 11 and Comparative Example 4.

FIG. 11 is a cross-sectional view showing a part of louver fins of a conventional heat exchanger.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a perspective cut-out explanatory view partially showing a fin and its vicinity of a heat exchanger such as an evaporator for use in car air-conditioners according to an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view showing the louver fin applied to the heat exchanger of the aforementioned embodiment, and FIG. 3 is an enlarged cross-sectional view of the front portions of the fins of the heat exchanger according to the aforementioned embodiment. In the following explanation, for the purpose of facilitating the understanding of the present invention, the explanation will be made by assuming that the direction along the air introduction direction X with respect to the heat exchanger of the embodiment is a front-and-rear direction of the heat exchanger.

As shown in these figures, in this heat exchanger, a plurality of flat heat exchanging tubes 1 and 2 each extending in the direction perpendicular to the air introduction direction X (i.e., the up-and-down direction) are arranged in parallel with each other at certain intervals along the right-and-left direction of the heat exchanger in two rows. Disposed between the adjacent heat exchanging tubes 1 and 1 (2 and 2) arranged in the widthwise direction of the heat exchanger is a corrugated fin 3.

The corrugated fin 3 is provided with a plurality of thin louver fins 4 as heat transfer plates extending in the front-and-rear direction and arranged in the up-and-down direction at certain intervals with their sides connected alternatively to thereby form a meandering shape. Between the adjacent louver fins 4 of the corrugated fin 3, an air passage 6 extending in the front-and-rear direction is formed, so that the air A as heat medium will be introduced into each air passage 6 from the front side of the heat exchanger during the operation.

Each louver fin 4 is provided with a plurality of louvers 5 formed by cutting and bending a certain region of the louver fin at certain intervals in the front-and-rear direction. Thus, the air A entered into the air passages 6 will be guided by the louvers 5 into the louver gaps each formed between the adjacent louvers 5, so that heat exchanging is performed between the air A and the refrigerant passing through the heat exchanging tubes 1 via the fin.

In this embodiment, when the length of the louver along which the air passes is defined as a louver width, the aforementioned plurality of louvers 5 in each louver fin 4 includes wide louvers 5 a each having a large louver width and narrow louvers 5 b each having a small louver width, and the wide louver and the narrow louver are disposed alternatively.

In this embodiment, when the louver width of the wide louver 5 a is represented as “Lwl,” it is preferable to set the width Lwl to 0.8 to 1.3 mm. It is more preferable to set the lower limit to 0.85 mm or more and the upper limit to 1.2 mm or less. Further, when the louver width of the narrow louver 5 b is represented as “Lws,” it is preferable to set the width Lws to 0.1 to 0.6 mm. It is more preferable to set the lower limit to 0.15 mm or more.

Too small or too large louver width Lwl or Lws causes a deterioration of the heat transfer rate of the louver fin 4 because of the generated bypass flow of the air or the increased pressure loss, resulting in deteriorated heat exchanging performance.

Furthermore, in this embodiment, it is preferable to set the ratio Lws/Lwl of the louver width “Lws” of the narrow louver 5 b to the louver width Lwl of the wide louver 5 a to 0.1 to 0.7. It is more preferable to set the lower limit to 0.3 or more.

As will be apparent from Examples which will be mentioned later, too small or too large louver width ratio Lws/Lwl causes a deterioration of the heat transfer rate of the louver fin 4 because of the generated bypass flow of the air or the increased pressure loss, resulting in deteriorated heat exchanging performance.

Furthermore, in this embodiment, the angle La of each louver 5 (louver angle) with respect to the louver fin 4 as a heat transfer plate is set to be almost constant. It is preferable to set the louver angle La to 22 to 36°. More preferably, the lower limit and the upper limit are set to 24° or more and 32° or less, respectively.

Too small or too large louver angle La causes a deterioration of the heat transfer rate of the louver fin because of the generated bypass flow of the air or the increased pressure loss, resulting in deteriorated heat exchanging performance.

Furthermore, in this embodiment, the distance between the adjacent louver fins 4 and 4, i.e., the fin pitch Fp, is preferably set to 1 to 2 mm. More preferably, the upper limit is set to 1.6 mm or less.

As will be apparent from Examples which will be mentioned later, too small or too large fin pitch Fp causes a deterioration of the heat transfer rate of the louver fin 4 because of the generated bypass flow of the air or the increased pressure loss, resulting in deteriorated heat exchanging performance.

Furthermore, in this embodiment, the ratio Fp/Lwl of the fin pitch Fp to the louver width Lwl of the wide louver 5 a is preferably set to 1 or more. If this ratio is too small or too large, the heat transfer rate may deteriorate because of the generated bypass flow of the air or the increased pressure loss, resulting in deteriorated heat exchanging performance.

In this invention, in cases where the plurality of louvers 5 include three or more kinds of louvers different in width, it is preferable to set the ratio Fp/Lwmax of the fin pitch Fp to the widest louver width Lwmax to 1 or more in the same manner as mentioned above.

In the heat exchanger of this embodiment, since the plurality of louvers 5 of each louver fin 4 include wide louvers 5 a and narrow louvers 5 b arranged alternatively, the air A entered into the air passages 6 will be guided by the louvers 5 into the louver gaps each formed between the adjacent louvers 5, thereby causing the air A to smoothly flow along each louver 5. This improves the heat transfer rate by preventing the generation of bypass flow of the air A, resulting in excellent heat exchanging performance.

In the aforementioned embodiment, although the plurality of louvers 5 of each louver fin 4 include two kinds of louvers, wide louvers 5 a and narrow louvers 5 b, arranged alternatively, in the present invention, the kind of louver or the arrangement thereof are not limited to the above. For example, the plurality of louvers may include one or plural wide louvers and one or plural narrow louvers arranged alternatively. In short, the present invention covers various embodiments so long as the plurality of louvers include two or more kinds of louvers different in louver width arranged in a mixed manner. For example, it can be constituted such that the wide louvers 5 a are arranged at the windward side and the narrow louvers 5 b are arranged at the leeward side as shown in FIG. 4(a); the narrow louvers 5 b are arranged between the wide louvers 5 a as shown in FIG. 4(b); one or more narrow louvers 5 b and one or more wide louvers 5 a are arranged alternatively as shown in FIGS. 4(c) to 4(e); and the wide louvers 5 a and the narrow louvers 5 b are arranged randomly.

In the aforementioned embodiments, although the explanation is directed to the case in which the present invention is applied to a heat exchanger such as an evaporator, the present invention is not limited to it, but can also be applied to a heat exchanger such as a condenser or a heater core. Furthermore, the heat exchanger is not limited to a heat exchanger for use in car air-conditioners, but can be used as a heat exchanger for use in room air-conditioners, refrigerators, another refrigeration apparatuses or heaters.

Furthermore, in the aforementioned embodiments, although the explanation is directed to the case in which the present invention is applied to corrugated fins, the present invention is not limited to it, but can also be applied to plate fins in which adjacent heat transfer fins are disposed independently.

Furthermore, in the aforementioned embodiment, although the explanation is directed to the case in which the present invention is applied to a fin for transferring heat by air, the present invention is not limited to it, but can be applied to a fin for transferring heat by heat medium other than air.

EXAMPLES

Hereinafter, Examples related to the present invention and Comparative Examples which deviate from the gist of the present invention will be explained.

In accordance with the aforementioned embodiment, evaporators for car air-conditioners in which corrugated fins with different kinds of louvers were arranged between the adjacent flat heat exchanging tubes were examined.

Examples 1 to 5

TABLE 1 Lwl (mm) Lws (mm) Lws/Lwl Fp (mm) La (°) Example 1 1.1 0.167 0.152 1.3 26 Example 2 1.0 0.333 0.333 1.3 26 Example 3 1.0 0.50 0.50 1.3 26 Example 4 0.85 0.583 0.686 1.3 26 Example 5 0.85 0.65 0.765 1.3 26 Comparative 0.75 0.75 1.0 1.3 26 Example 1 Lwl: width of wide louver (mm) Lws: width of narrow louver (mm) Lws/Lwl: louver width ratio Fp: fin pitch (mm) La: louver angle (°)

In Table 1, the evaporator of Example 1 was provided with corrugated fins having a plurality of louver fins each including wide louvers and narrow louvers arranged alternatively. The louver width Lwl of the wide louver was 1.1 mm, the louver width Lws of the narrow louver was 0.167 mm, the louver angle La was 26°, the fin pitch Fp was 1.3 mm and the louver width ratio Lws/Lwl was 0.152.

In the evaporator of Example 2, the louver width Lwl of the wide louver was set to 1.0 mm, and the louver width Lws of the narrow louver was set to 0.333 mm. The remaining dimensions were set to the same as those in Example 1. The louver width ratio Lws/Lwl was 0.333.

In the evaporator of Example 3, the louver width Lwl of the wide louver was set to 1.0 mm, and the louver width Lws of the narrow louver was set to 0.5 mm. The remaining dimensions were set to the same as those in Example 1. The louver width ratio Lws/Lwl was 0.50.

In the evaporator of Example 4, the louver width. Lwl of the wide louver was set to 0.85 mm, and the louver width Lws of the narrow louver was set to 0.583 mm. The remaining dimensions were set to the same as those in Example 1. The louver width ratio Lws/Lwl was 0.686.

In the evaporator of Example 5, the louver width Lwl of the wide louver was set to 0.85 mm, and the louver width Lws of the narrow louver was set to 0.65 mm. The remaining dimensions were set to the same as those in Example 1. The louver width ratio Lws/Lwl was 0.765.

In the evaporator of Comparative Example 1, the corrugated fin had a plurality of louvers arranged at a constant louver width (louver pitch) of 0.75 mm. The remaining dimensions were set to the same as those in Example 1.

Regarding the aforementioned evaporators, each heat transfer rate with respect to the front wind velocity was measured by computer simulation. The results are shown in the graph of FIG. 5.

As will be apparent from the graph, the evaporators of Examples 1 to 5 were higher than the evaporator of Comparative Example 1 in heat transfer rate by 10 to 20% at the entire front wind velocity region, and therefore excellent in heat exchanging performance. Especially in the state of low speed driving state whose front wind velocity was 2 m/s or less or the idling state, the heat transfer rate was excellent.

Furthermore, the evaporator of Example 1 was higher than the evaporator of Example 2 in heat transfer rate.

Among Examples 1 to 5, in each of Examples 1 to 4 in which the ratio Lws/Lwl of the louver width Lws of the narrow louver to the louver width Lwl of the wide louver was 0.1 to 0.7, the heat transfer rate was more stabilized than that of Example 5 in which the louver width ratio Lws/Lwl exceeded 0.7. Among other things, in each of Examples 2 to 4 in which the louver width ratio Lws/Lwl was 0.3 to 0.7, sufficient heat transfer rate was obtained at the entire front wind velocity region.

Examples 6, 7

TABLE 2 Lwl (mm) Lws (mm) Lws/Lwl Fp (mm) La (°) Example 6 1.0 0.333 0.333 1.3 28 Example 7 1.0 0.50 0.50 1.3 28 Comparative 0.75 0.75 1.0 1.3 28 Example 2 Lwl: width of wide louver (mm) Lws: width of narrow louver (mm) Lws/Lwl: louver width ratio Fp: fin pitch (mm) La: louver angle (°)

As shown in Table 2, the evaporator of Example 6 was prepared in the same manner as the aforementioned Example 2 except that the louver angle La was set to 28°.

The evaporator of Example 7 was prepared in the same manner as the aforementioned Example 3 except that the louver angle La was set to 28°.

The evaporator of Comparative Example 2 was prepared in the same manner as the aforementioned Comparative Example 1 except that the louver angle La was set to 28°.

Regarding the aforementioned evaporators, each heat transfer rate with respect to the front wind velocity was measured by computer simulation. The results are shown in the graph of FIG. 6.

As will be apparent from the graph, even in the case in which the louver angle La is set to 28°, the evaporators of Examples 6 and 7 were higher than the evaporator of Comparative Example 2 in heat transfer rate at the entire front wind velocity region, and therefore excellent in heat exchanging performance. Especially in the state of low speed driving state whose front wind velocity was 2 m/s or less or the idling state, the heat transfer rate was high.

Examples 8, 9

TABLE 3 Lwl (mm) Lws (mm) Lws/Lwl Fp (mm) La (°) Example 8 1.0 0.333 0.333 1.3 — Example 9 1.0 0.50 0.50 1.3 — Comparative 0.75 0.75 1.0 1.3 — Example 3 Lwl: width of wide louver (mm) Lws: width of narrow louver (mm) Lws/Lwl: louver width ratio Fp: fin pitch (mm) La: louver angle (°)

Evaporators of Examples 8 and 9 and Comparative Example 3 were prepared in the same manner as in the aforementioned Examples 2 and 3 and Comparative Example 1 except that the louver angle La was set to parameter.

In each of these evaporators, each heat transfer rate with respect to the louver angle La in the state in which the front wind velocity was 1 m/s and 2 m/s was measured by computer simulation. These results are shown in the graphs of FIGS. 7 and 8.

As will be apparent from both graphs, in the case where the air velocity was 1 m/s, as compared with the evaporator of Comparative Example 3, the evaporators of Examples 8 and 9 were extremely higher in thermal transfer coefficient at the louver angle 17 to 36°, and slightly higher at the louver angle exceeding 36°. Furthermore, in the case where the air velocity was 2 m/s, the heat transfer rate of each of Examples 8 and 9 was higher at the louver angle of 17 to 31°. To the contrary, in the case where the louver angle exceeds 30°, significant difference could not be recognized between Examples and Comparative Example.

As shown in FIG. 7, in the idling state (in the state of the front wind velocity of 1 m/s) in which it is difficult to attain high performance, in the evaporators of Examples 8 and 9, high heat transfer rate could be obtained at the louver angle La of 22 to 36°. In the case where the lower limit was 24° or more and the upper limit was 32° or less, higher heat transfer rate could be obtained.

Furthermore, as shown in FIG. 8, in the case where the front wind velocity of 2 m/s, high heat transfer rate could be obtained at the louver angle La of 20 to 30°. In the case where the lower limit was 22° or more and the upper limit was 28° or less, higher heat transfer rate could be obtained.

Examples 10 and 11

TABLE 4 Lwl (mm) Lws (mm) Lws/Lwl Fp (mm) La (°) Example 10 1.0 0.333 0.333 — 26 Example 11 1.0 0.50 0.50 — 26 Comparative 0.75 0.75 1.0 — 26 Example 4 Lwl: width of wide louver (mm) Lws: width of narrow louver (mm) Lws/Lwl: louver width ratio Fp: fin pitch (mm) La: louver angle (°)

As shown in Table 4, evaporators of Examples 10 and 11 and Comparative Example 4 were prepared in the same manner as in the aforementioned Examples 2 and 3 and Comparative Example 1 except that the fin pitch Fp was set to parameter.

In each of these evaporators, each heat transfer rate with respect to the fin pitch Fp in the state where the front wind velocity was 1 m/s and 2 m/s was measured by computer simulation. These results are shown in the graphs of FIGS. 9 and 10.

As will be apparent from both graphs, in the case where the air velocity was 1 m/s and 2 m/s, as compared with the evaporator of Comparative Example 4, the evaporators of Examples 10 and 11 were extremely higher in heat transfer rate at the fin pitch Fp of 1.0 to 2.4 mm.

Especially, in the evaporators of Examples 10 and 11, in the case where the fin pitch Fp was 1.6 mm or less, sufficient heat transfer rate was obtained.

In the heat exchanger fin according to the invention, since a plurality of louvers include plural kinds of louvers different in louver width, the heat medium such as air will be assuredly introduced into the lower gaps each formed between adjacent louvers to flow smoothly along each louver, resulting in improved heat transfer rate by preventing generation of bypass flow.

The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intent, in the use of such terms and expressions, of excluding any of the equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed.

INDUSTRIAL APPLICABILITY

The present invention can be applied to a heat exchanger such as a car air-conditioning condenser or evaporator, and also to a heat exchanger fin such as a louver fin or a corrugated fin to be equipped to the heat exchanger. 

1. A heat exchanger fin, comprising: a heat transfer plate disposed in parallel to a heat medium introduction direction and provided with a plurality louvers arranged at certain intervals in the heat medium introduction direction, said plurality of louvers being formed by cutting and bending said heat transfer plate so that the heat medium is passed while being guided by said plurality of louvers, wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the heat medium passes, and wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement along the heat medium introduction direction.
 2. The heat exchanger fin as recited in claim 1, wherein said plurality of louvers include wide louvers each having a wide louver width and narrow louvers each having a narrow louver width, wherein said wide louvers and said narrow louvers are disposed in a mixed arrangement.
 3. The heat exchanger fin as recited in claim 2, wherein one or a plurality of said wide louvers and one or a plurality of said narrow louvers are arranged alternatively.
 4. The heat exchanger fin as recited in claim 2, wherein said wide louver and said narrow louver are arranged alternatively.
 5. The heat exchanger fin as recited in claim 2, wherein when a louver width of said wide louver and a louver width of said narrow louver are represented as “Lwl” and “Lws,” respectively, a ratio “Lws/Lwl” of said louver width “Lws” of said narrow louver to said louver width “Lwl” of said wide louver is set to 0.1 to 0.7.
 6. The heat exchanger fin as recited in claim 1, wherein an angle of said louver with respect to said heat transfer plate is set to 22 to 36°.
 7. The heat exchanger fin as recited in claim 1, wherein a plurality of said heat transfer plates are arranged in parallel with each other at certain intervals in a direction perpendicular to the heat medium introduction direction to form an air passage between adjacent heat transfer plates.
 8. The heat exchanger fin as recited in claim 7, wherein a fin pitch defined by a distance between adjacent heat transfer plates is set to 1 to 2 mm.
 9. The heat exchanger fin as recited in claim 7, wherein when a fin pitch defined by a distance between adjacent heat transfer plates is represented as “Fp” and a louver width of a widest louver having a widest width is represented as “Lwmax,” a ratio “Fp/Lwmax” of said fin pitch “Fp” with respect to said louver width “Lwmax” is set to 1 or more.
 10. The heat exchanger fin as recited in claim 1, wherein said heat transfer plate is disposed between said pair of heat exchanging tubes arranged in parallel with each other at a certain distance to exchange heat between air as a heat medium passing through said pair of heat exchanging tubes and refrigerant passing through said heat exchanging tube.
 11. The heat exchanger fin as recited in claim 10, wherein it is configured such that refrigerant is condensed by exchanging heat with air.
 12. The heat exchanger fin as recited in claim 10, wherein it is configured such that refrigerant is evaporated by exchanging heat with air.
 13. A louver fin, comprising: a heat transfer plate disposed in parallel to a heat medium introduction direction and provided with a plurality louvers arranged at certain intervals in the heat medium introduction direction, said plurality of louvers being formed by cutting and bending said heat transfer plate so that the heat medium is passed while being guided by said plurality of louvers, wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the heat medium passes, and wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement along the heat medium introduction direction.
 14. A corrugated fin, comprising: a plurality of heat transfer plates disposed in parallel to a heat medium introduction direction and arranged in parallel at certain intervals in a direction perpendicular to the heat medium introduction direction with adjacent heat transfer plates connected with each other, each of said plurality of heat transfer plates being provided with a plurality louvers arranged at certain intervals in the heat medium introduction direction, said plurality of louvers being formed by cutting and bending said heat transfer plate so that the heat medium is passed while being guided by said plurality of louvers, wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the heat medium passes, and wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.
 15. A heat exchanger, comprising a plurality of heat exchanger fins disposed in parallel to an air introduction direction and arranged in parallel at certain intervals in a direction perpendicular to the air introduction direction, and a refrigerant passage through which refrigerant passes, each of said plurality of heat transfer plates being provided with a plurality louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to exchange heat between the air and the refrigerant, wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the heat medium passes, and wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.
 16. A heat exchanger, comprising a pair of heat exchanging tubes disposed in parallel at a certain interval, and a plurality of heat exchanger fins each disposed in parallel to an air introduction direction and arranged in parallel with each other at certain intervals in a direction perpendicular to the air introduction direction, and each of said plurality of heat exchanger fins being provided with a plurality louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to exchange heat between the air and the refrigerant, wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the air passes, and wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.
 17. The heat exchanger as recited in claim 15, wherein said plurality of louvers include wide louvers each having a wide louver width and narrow louvers each having a narrow louver width, wherein said wide louvers and said narrow louvers are disposed in a mixed arrangement.
 18. The heat exchanger as recited in claim 15, wherein adjacent fins among said plurality of heat exchanger fins are joined with each other.
 19. A condenser, comprising a plurality of heat exchanger fins disposed in parallel to an air introduction direction and arranged in parallel at certain intervals in a direction perpendicular to the air introduction direction, and a refrigerant passage through which refrigerant passes, each of said plurality of heat transfer plates being provided with a plurality of louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to condense the refrigerant by exchanging heat between the air and the refrigerant, wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the heat medium passes, and wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.
 20. A condenser, comprising a pair of heat exchanging tubes disposed in parallel at a certain interval, and a plurality of heat exchanger fins each disposed in parallel to an air introduction direction and arranged in parallel with each other at certain intervals in a direction perpendicular to the air introduction direction, and each of said plurality of heat exchanger fins being provided with a plurality of louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to condense refrigerant by exchanging heat between the air and the refrigerant, wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the air passes, and wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.
 21. The condenser as recited in claim 19, wherein said plurality of louvers include wide louvers each having a wide louver width and narrow louvers each having a narrow louver width, wherein said wide louvers and said narrow louvers are disposed in a mixed arrangement.
 22. The condenser as recited in claim 19, wherein adjacent fins among said plurality of heat exchanger fins are joined with each other.
 23. A condenser for use in car air-conditioning refrigeration cycles, comprising: a plurality of heat exchanger fins disposed in parallel to an air introduction direction and arranged in parallel at certain intervals in a direction perpendicular to the air introduction direction; and a refrigerant passage through which refrigerant passes, wherein each of said plurality of heat transfer plates is provided with a plurality of louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to condense the refrigerant by exchanging heat between the air and the refrigerant, and wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the heat medium passes, and wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.
 24. A condenser for use in car air-conditioning refrigeration cycles, comprising: a pair of heat exchanging tubes disposed in parallel at a certain interval; and a plurality of heat exchanger fins each disposed in parallel to an air introduction direction and arranged in parallel with each other at certain intervals in a direction perpendicular to the air introduction direction, wherein each of said plurality of heat exchanger fins is provided with a plurality of louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to condense refrigerant by exchanging heat between the air and the refrigerant, wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the air passes, and wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.
 25. An evaporator, comprising a plurality of heat exchanger fins disposed in parallel to an air introduction direction and arranged in parallel at certain intervals in a direction perpendicular to the air introduction direction, and a refrigerant passage through which refrigerant passes, each of said plurality of heat transfer plates being provided with a plurality of louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to evaporate the refrigerant by exchanging heat between the air and the refrigerant, wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the heat medium passes, and wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.
 26. An evaporator, comprising a pair of heat exchanging tubes disposed in parallel at a certain interval, and a plurality of heat exchanger fins each disposed in parallel to an air introduction direction and arranged in parallel with each other at certain intervals in a direction perpendicular to the air introduction direction, and each of said plurality of heat exchanger fins being provided with a plurality of louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to evaporate refrigerant by exchanging heat between the air and the refrigerant, wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the air passes, and wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.
 27. The evaporator as recited in claim 25, wherein said plurality of louvers include wide louvers each having a wide louver width and narrow louvers each having a narrow louver width, wherein said wide louvers and said narrow louvers are disposed in a mixed arrangement.
 28. The evaporator as recited in claim 25, wherein adjacent fins among said plurality of heat exchanger fins are joined with each other.
 29. An evaporator for use in car air-conditioning refrigeration cycles, comprising: a plurality of heat exchanger fins disposed in parallel to an air introduction direction and arranged in parallel at certain intervals in a direction perpendicular to the air introduction direction; and a refrigerant passage through which refrigerant passes, wherein each of said plurality of heat transfer plates is provided with a plurality of louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to evaporate the refrigerant by exchanging heat between the air and the refrigerant, and wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the heat medium passes, and wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement.
 30. An evaporator for use in car air-conditioning refrigeration cycles, comprising: a pair of heat exchanging tubes disposed in parallel at a certain interval; and a plurality of heat exchanger fins each disposed in parallel to an air introduction direction and arranged in parallel with each other at certain intervals in a direction perpendicular to the air introduction direction, wherein each of said plurality of heat exchanger fins is provided with a plurality of louvers arranged at certain intervals in the air introduction direction, said plurality of louvers being formed by cutting and bending said heat exchanger fin so that the air is passed while being guided by said plurality of louvers to evaporate the refrigerant by exchanging heat between the air and the refrigerant, wherein said plurality of louvers include plural kinds of louvers different in louver width, said louver width being defined by a length of said louver along which the air passes, and wherein said plural kinds of louvers different in louver width are disposed in a mixed arrangement. 